Project Summary Low back pain (LBP) is the most prevalent secondary condition in Parkinson disease (PD), affecting up to 74% of patients. In the general population, LBP causes significant morbidity, but the effect of LBP in patients with PD is not well understood and treatment options are lacking. Non-steroidal anti-inflammatory drugs provide insufficient pain relief. Opioid pain medications are addictive and may worsen PD manifestations like cognitive impairment and constipation. Surgery has high failure and complication rates in PD. Consequently, LBP is often not addressed. Physical therapy effectively reduces LBP in the general population and may provide an effective treatment option for LBP in patients with PD. However, people with PD have disease-specific characteristics that warrant consideration in treatment development. As such, tailoring physical therapy for LBP in PD requires a better understanding of the multi-factorial nature of LBP in this population. The overall goal of this cross-sectional investigation is to comprehensively characterize LBP in PD. We will determine whether and how factors known to contribute to LBP (e.g., biomechanical, sensory, and psychologic impairments) differ between people with PD and older adults. Further, we will explore how these impairments contribute to LBP-related disability in people with PD. Our central hypothesis is that LBP in PD is different (i.e., greater severity of biomechanical, sensory, and psychologic impairments) from LBP in older adults. This investigation complements NCMRR?s mission to enhance health and quality of life in people with disabilities by beginning to understand LBP in PD. This study will help to inform the development of effective interventions to address it. Dr. Duncan?s career goal is to understand and ultimately prevent or reduce the burden of secondary musculoskeletal pain conditions in people with primary neurologic disease. Dr. Duncan?s career development plan will focus on education in the following areas: 1) the multi-factorial nature of pain from a clinical perspective, 2) the interaction between pain and PD, and 3) advanced statistics (e.g., multiple regression modeling). Dr. Duncan will receive mentorship from Dr. Joel Perlmutter and Dr. Linda Van Dillen, who are world-renowned experts in PD and LBP, respectively. This investigation will take place at Washington University in St. Louis School of Medicine, an internationally acclaimed research institution. The Movement Disorders Center, which follows more than 2,500 people with PD, will provide more than sufficient access to the sample required for this investigation. Information gained from this study will lay the foundation for development of therapeutic interventions for LBP in PD, which may reduce disability and improve quality of life.